HTML defer Attribute
<script src="demo/demo-async.js" defer></script>
The defer attribute specifies that the browser might defer execution of the script enclosed by the <script> element.
- async attribute is present: The script is downloaded in parallel to parsing the page, and executed as soon as it is available.
- defer attribute is present (and not async attribute): The script is downloaded in parallel to parsing the page, and executed after the page has finished parsing.
- Absence of async or defer: The script is downloaded and executed immediately, blocking parsing until the script is completed.
- The async attribute is only used for external scripts.
HTML: <element defer>
XHTML: <element defer="defer">
The defer attribute can be used on the following element:
|This is a boolean attribute, the presence of a boolean attribute on an element represents the true value, and the absence of the attribute represents the false value.